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Scheme of work – Cambridge IGCSE® Biology (0610)
Unit 10: Human influences on the environment
Recommended prior knowledge
Students should have covered Unit 9 Organisms and environment before beginning Unit 10.
Context
This unit builds on ideas studies in Unit 9, and brings together knowledge from many other areas of the syllabus such as cell division.
Outline
General features of population growth are considered, before looking in particular at problems associated with human population growth. A number of different
effects of the growing human population on the environment are then considered. Some of these are complex issues, with no straightforward answers, and
students should be encouraged to discuss and debate them. There is some opportunity to interpret data from population graphs and pollution data.
(Please note: (S) in bold denotes material in the Supplement (Extended syllabus) only)
Syllabus ref
IV 4
v1 2Y05
Learning objectives
10.1 Population size
• Define population as a group of
organisms of one species, living in
the same area at the same time
• State the factors affecting the rate of
population growth of an organism
(limited to food supply, predation
and disease), and describe their
importance.
• Identify:
- the lag
- the exponential (log)
- the stationary
- the death
- phases in the sigmoid population
growth curve for a population
growing in an environment with
Suggested teaching activities
Adequate food will enable the organisms to breed and to
produce more offspring. A shortage of food can result in
death, emigration and a decrease in the population.
Predation can illustrate the delayed effect of the population
and graphs to illustrate this are helpful. The interrelated
populations of the snowshoe hare and the lynx in Canada is
a clear example.
Disease can spread quickly in crowded populations like
myxomatosis that killed many rabbits in the UK about 40
years ago.
The class could discuss how populations grow.
Simple sketch graphs should be drawn to illustrate population
growth, and possible factors that might cause a levelling off in
population growth should be considered.
Extension – modelling population growth.
Cambridge IGCSE Biology (0610)
Learning resources
Biology for IGCSE, Williams et al.
Nelson Thornes, 2009 p236–239
Revision – Ecology (human
influences and conservation):
www.lgfl.skoool.co.uk/content/keyst
age4/biology/pc/lessons/uk_ks4_ec
ology/h-frame-ie.htm
Revision – Populations:
www.lgfl.skoool.co.uk/content/keyst
age4/biology/pc/lessons/uk_ks4_po
pulations/h-frame-ie.htm
Video clip – Bacterial growth:
www.bbc.co.uk/learningzone/clips/b
acterial-growth/209.html
1
Syllabus ref
Learning objectives
Suggested teaching activities
limited resources
• Describe the increase in the human
population size and its social
implications
• Interpret graphs and diagrams of
human population growth
The ideas developed in the previous section are now applied
to human population growth. Graphs showing how the human
population has changed over the last two centuries and
predictions for the future should be drawn. Students could be
introduced to population pyramids and their interpretation for
their own country.
Comparisons could be made between developed and less
developed countries and this would form a link with
Geography for some students. They should discuss the
possible implications of continued growth of the world human
population, if possible with reference to particular examples
collected from newspapers and other sources of up-to-date
information and data. To include food and water shortages.
Reference to Unit 7.3 Methods of birth control.
IV 4
Learning resources
Student progress could be assessed using
May/June 2010 Paper 0610/22 question 4
Oct/Nov 2010 Paper 0610/21 question 2
Oct/Nov 2009 Paper 0610/02 question 5
May/June 2008 Paper 0610/02 question 8
IV 4 (S)
IV 5
v1 2Y05
Video clip – Bacterial growth:
www.bbc.co.uk/learningzone/clips/b
acterial-growth/209.html
10.1 Supplement
• Explain the factors that lead to
- the lag phase
- exponential (log) phase
- stationary phase
in the sigmoid curve of population
growth, making reference, where
appropriate, to the role of limiting
factors
Limiting factors affect the size of the population such as lack
of food when the population is too big for the available
resources.
10.2 Human Influences on the
ecosystem
• outline the effects of humans on
ecosystems, with emphasis on
examples of international
importance:
- tropical rain forests
- oceans
- important rivers
This should be related both to the students' own country, and
to other countries around the world. Students should be able
to refer to one specific example of pollution in rain forests,
oceans and important rivers.
Video clip – Threat to rain forest:
www.bbc.co.uk/learningzone/clips/n
atural-balance-threats-to-therainforest/4712.html
There are many relevant websites relating to human
influences on the environment.
Video clip – Sea and river pollution:
www.bbc.co.uk/learningzone/clips/
why-have-fish-stocks-decreased-inthe-north-sea-pt-1-2/4687.html
Lack of oxygen may affect a fish population in a polluted lake.
Student progress could be assessed using:
Oct/Nov 2010 Paper 0610/31 question 6
Cambridge IGCSE Biology (0610)
2
Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
Ideas to consider are the introduction of machinery:
• tractors to replace draught animals, specialised
machinery to sow and to harvest crops like carrots
and wheat
• the increasing use of pesticides and fertilisers
• the breeding of new high-yielding crop varieties.
Student progress could be assessed using:
Oct/Nov 2010 Paper 0610/22 question 4
IV 5.1
10.3 Agriculture
• List the undesirable effects of
deforestation:
- extinction
- loss of soil
- flooding
- carbon dioxide build up
• Describe the over-use of fertilisers
to include:
- eutrophication of lakes and rivers
Deforestation may already have been considered in relation
to the carbon cycle and more wide-ranging effects should be
considered, such as loss of habitat and biodiversity and the
increased soil erosion and flooding.
Video clips – Deforestation:
www.bbc.co.uk/learningzone/clips/r
ainforest-destruction-kalimantanindonesia-and-costa-rica/3096.html
The flooding of the river Indus in Pakistan in 2010 could be
discussed or the Three Gorges dam on the Yangtze River in
China. It is a good idea to try to introduce at least one
specific example, as well as discussing the problems in
general.
www.bbc.co.uk/learningzone/clips/s
ustainable-forestry-using-animalpower/11966.html
The use of fertilisers containing nitrate can be concentrated
on here and related back to the nitrogen cycle (dealt with in
Unit 9.3 Nutrient cycles). Ensure that students realise that
both organic (for example manure) and inorganic fertilisers
can cause pollution problems.
Leaching into waterways and subsequent eutrophication,
should be described and explained.
Extension – possible solutions to eutrophication could be
researched.
Student progress could be assessed using:
May/June 2011 Paper 0610/31 question 2d
Oct/Nov 2010 Paper 0610/33 question 4
v1 2Y05
Cambridge IGCSE Biology (0610)
3
Syllabus ref
IV 5.2
IV 5.2 (S)
Learning objectives
Suggested teaching activities
Learning resources
10.4 Pollution
• Describe the undesirable effects of
pollution to include:
- water pollution by sewage and
chemical waste
- air pollution by sulfur dioxide
- air pollution by greenhouse gases
(carbon dioxide and methane)
contributing to global warming
- pollution due to pesticides
including insecticides and
herbicides
- pollution due to nuclear fall-out
Students could research recent news articles on different
types of pollution and report back.
Biology for IGCSE, Williams et al.
Nelson Thornes, 2009 p242–249
Show video clip – pollution:
www.bbc.co.uk/learningzone/clips/the-effect-of-humanactivity-on-the-environment/4173.html
Practical Biology – Indicator
Species:
www.nuffieldfoundation.org/practica
l-biology/monitoring-water-pollutioninvertebrate-indicator-species
10.4
• Discuss the effects of nonbiodegradable plastics in the
environment
• Discuss the causes and effects
on the environment of acid rain
and the measures that might be
taken to reduce its incidence
• Explain how increases in
greenhouse gases, carbon
dioxide and methane are thought
to cause global warming
Non-biodegradable materials will be detrimental to the
environment if they are put in land fill sites. There is also a
problem of too many huge land fill sites in many countries.
Biodegradable plastics are being produced that are slow to
be decomposed but this is an improvement on the removal of
plastic waste and its recycling.
www.bbc.co.uk/learningzone/clips/carbon-dioxide-in-theatmosphere/4417.html
Extension – different types of pesticide could be studies (link
to bioaccumulation).
Student progress could be assessed using:
Oct/Nov 2010 Paper 0610/21 question 7
Extension:
Science Around the World – Acid
Rain:
www.nationalstemcentre.org.uk/elib
rary/resource/1728/acid-rain
Explain why plastics will produce air pollution if they are burnt
in an incinerator.
Video clip:
www.bbc.co.uk/learningzone/clips/a
ir-pollution-and-its-effects-on-theenvironment/6008.html
The environmentally friendly option is to recycle materials
such as paper, glass, metal and batteries. This reduces
environmental pollution and saves energy in production costs
although there is some disagreement about paper recycling
as the chlorine required to bleach the paper and the
temperature require energy.
Acid rain investigation:
www.saps.org.uk/secondary/teachi
ng-resources/186-student-sheet-5investigating-seed-germination
Students should understand that acid rain is caused by sulfur
dioxide (released from the burning of oil and coal, for
example in power stations) and nitrogen oxides (present, for
example, in car exhausts). They should know something of
the biological effects of acid rain.
v1 2Y05
Cambridge IGCSE Biology (0610)
4
Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
Extension: students could investigate the effects of acid on
germination rate.
Discussion about the effect of greenhouse gases on climate
should be discussed. The fact that no agreement has been
made globally is relevant and many students will have an
opinion on this problem that has many factors to be
considered besides burning of wood and fossil fuels.
Student progress could be assessed using:
May/June 2010 Paper 0610/31 question 4
May/June 2010 Paper 0610/32 question 6
IV 5.3
10.5 Conservation
• Describe the need for conservation
of:
- species and their habitats
- natural resources (water)
- and non-renewable materials
including fossil fuels
It is best to look at some specific examples, either relating to
the students' home country, or of international importance
such as: tigers in India, elephants in Africa, sun bears from
Cambodia or orangutans in Borneo.
Extension – Students could become involved in the Science
Around the World conservation project.
Student progress could be assessed using:
May/June 2008 Paper 0610/31 question 2
May/June 2008 Paper 0610/32 question 2
Biology for IGCSE, Williams et al.
Nelson Thornes, 2009 p250–253
Science Around the World –
Conserving Biodiversity:
www.nationalstemcentre.org.uk/elib
rary/resource/1738/biodiversityaround-us
Video clips – Conservation:
www.bbc.co.uk/learningzone/clips/b
iodiversity-and-the-humanimplications/5505.html
www.bbc.co.uk/learningzone/clips/l
och-lomond-land-useconservation/1142.html
IV 5.3 (S)
v1 2Y05
10.5
• Explain how limited and nonrenewable resources can be
recycled:
- recycling of paper
- treatment of sewage to make
the water that it contains safe
to return to the environment or
for human use
The influence of humans and the need for populations to
maintain their viable numbers could be discussed. The
importance of maintaining biodiversity on the planet for
ecosystems, chemical compounds used for medicines and
for their genetic diversity.
Tropical rainforests have millions of species that should be
preserved.
Cambridge IGCSE Biology (0610)
Video clip – Recycling:
www.bbc.co.uk/learningzone/clips/r
ecycling-and-the-incineration-ofwaste/1577.html
Video clips – Sewage:
www.bbc.co.uk/learningzone/clips/s
ewage-treatment/4199.html
5
Syllabus ref
Learning objectives
Suggested teaching activities
The practice of recycling and its importance is covered in
many aspects throughout the Cambridge IGCSE courses.
Learning resources
www.bbc.co.uk/learningzone/clips/
micro-organisms-at-work-in-asewage-farm/2278.html
Emphasis could be given to metals, batteries, glass as well
as paper.
Students should learn how sewage is dealt with in their own
local area, and there may be an opportunity to visit a sewage
treatment plant, or to obtain information from the water
company responsible for this.
Student progress could be assessed using:
Oct/Nov 2010 Paper 0610/32 question 5
v1 2Y05
Cambridge IGCSE Biology (0610)
6